The present invention relates to an optical system used in a laser scanner for acquiring point cloud data and a surveying instrument which comprises a function of a laser scanner and a function of a total station.
A laser scanner scans a distance measuring light within a predetermined measurement range, receives a reflection light and acquires point cloud data.
The laser scanner has a scanning mirror rotating around a single axis and is designed so as to reflect the distance measuring light emitted from a distance measuring light source by the scanning mirror, emit to the measurement range, and further scan by a rotation of the scanning mirror.
The scanning mirror normally has a structure of rotating over a total circumference at a high speed and is accommodated in a sealed container for protection. The container has a transmission window made of a cylindrical transparent member, and the distance measuring light is emitted through the transmission window or is received through the transmission window.
Since the transmission window is cylindrical, when the distance measuring light is transmitted through the transmission window, the distance measuring light is subjected to an optical action from the transmission window, the distance measuring light is diffused, and a luminous flux cross-section is largely expanded. For this reason, an irradiating spot diameter of the distance measuring light at an irradiation point becomes large, and a measurement with a high angular resolution becomes impossible. Further, a reflected distance measuring light to be received is also expanded. As a result, there is a problem that a small light receiving element cannot be used, and a dynamic range of a received light amount increases and a measurement accuracy deteriorates.